An increasing number of communication systems have been developed and standardized to support various communication servers and usage scenarios. For example, cellular mobile communication systems such as the Global System for Mobile communication (GSM) or the Universal System for Mobile Telecommunication (UMTS) have been widely deployed. In addition, a large number of standards for wireless networks have been developed including the Institute for Electrical and Electronic Engineers IEEE 802.11 series of standards developed for unregulated deployment with relatively small coverage areas for each access point or the IEEE 802.16 standards developed for regulated deployment with relatively large coverage areas for each access point.
Increasingly there is a desire for different types of networks and systems to be integrated. In particular, it has been proposed that heterogeneous communication systems may be deployed which incorporate a number of different access networks interconnected by a core network. Such heterogeneous communication systems may provide an improved user experience and service and may for example provide seamless handovers wherein a communication session may seamlessly be transferred between different access networks without user involvement or indeed without the user being aware of the handover.
However, a critical parameter for communication systems is the allocation and utilization of available resource. Conventionally, the access resource, such as the air interface resource for a wireless access network, is managed and controlled by the individual access network. However, for heterogeneous communication systems, this may result in increased complexity of the individual access network and a suboptimal interworking and resource sharing between the different access networks. Also, in many systems centralized operations are required to manage e.g. subscription related issues such as user authorization, billing and admission control.
Accordingly, it may be advantageous to perform resource and admission control centrally. However, providing a common centralized resource management approach is associated with a large number of problems and difficulties. In particular, in order to improve resource utilization, the admission of a new communication service should take into account the specific characteristics of the access network(s) that supports the communication service. However, this typically results in increased complexity and increased signaling overhead.
Hence, an improved approach for a heterogeneous communication system would be advantageous and in particular a system allowing reduced signaling, reduced complexity, increased reliability and/or improved admission control would be advantageous.